Method for stabilizing fuel oils with



United States Patent METHOD FOR STABILKZING FUEL OILS WITH ACTIVATEDION-EXCHANGE RESINS Harry L. Coonradt, Woodbury, and Wilbur K. Leaman,Medford Lakes, N. L, assignors to Socony Mobil Oil Company, Inc., acorporation of New York No Drawing. Application December 5, 1955 SerialNo. 550,879

3 Claims. (Cl. 196-23) The present invention relates to thestabilization of fuel oils and, more particularly, to a method forstabilizing fuel oils with respect to color and sedimentation.

Many distillate fuel oils of the type used both in domestic, i. e., homeburners, or industrial burners deteriorate in storage either withrespect to color or sedimentation or both. Several methods of treatmentare commonly known to increase the stability of these although nocompletely satisfactory explanation of the cause of the instability norof the mechanism whereby the fuel oil is stabilized have been advancedand accepted by those investigating this problem. Three commonlyemployed methods for stabilizing these fuel oils are acid treating,caustic treating and solvent treating. However, whether satisfactory ornot these methods of stabilizing fuel oils leave much to be desiredsince certain disadvantages are inherent in these methods such as wastedisposal, regeneration of the treating solution, excessive losses of oilbeing treated, etc.

Since the catalytic cracking of gas oil became a prominent factor in theproduction of gasoline to meet the increasing demands of the presentera, greater and greater amounts of oils derived from materials whichhave been subjected to catalytic cracking have found their ways into thefuel oils used in both domestic and industrial bumers. Consequently,except in a few isolated instances where special conditions can be metonly by the use of a straight run, i. e., oil which has not beensubjected to either thermal cracking or catalytic cracking, fuel oilsfor domestic and industrial burners are mixtures of cracked and straightrun oils. The straight run component by itself, untreated is relativelystable. The catalytically cracked stock alone is very unstable andblends of the catalytically cracked stock with straight run stocklikewise are very unstable with respect to color and/or sedimentation.In the treatment of these blends or mixtures by the method hereinafterdisclosed it has been found that whereas treatment solely of thestraight run component of the blend contributed very little to thestabilization of the mixture, treatment of the catalytically crackedcomponent only was sufficient to provide a mixture stabilized as tocolor and/or sedimentation. Accordingly, mixtures of straight run andcatalytically cracked fuel oils can be stabilized (l) by treating thecatalytically cracked component alone or (2) the mixture can be treated.Either of these treatments provides a mixture of fuel oil stabilizedwith respect to color and/or sedimentation.

Two methods of determining stability of fuel oil components or fuel oilmixtures with respect to color and sedimentation were employed wherebythe data presented hereinafter were obtained. These methods aredesignated (1) the 212 F. Stability Test which is of 24 hours durationand (2) the 110 F. Stability Test which, as employed in conjunction withthe present work, is either of three or six weeks duration.

Patented Apr. 22, 1958 ice In this test, 500 milliliters of the fuel tobe tested is stored in a beaker covered with a watch glass in amechanically convected oven at a temperature of 110 3:2 F. After aperiod of three, and again after a period of six weeks, i. e., six weekstotal, the contents of the beaker is examined to determine the color.The total amount of sediment is determined at the end of the test, i.e., either at the end of three weeks or at the end of six weekswhichever is the total elapsed time of the test.

The color of the fuel to be tested is measured photoelectrically interms of light transmission and correlated to the NPA color scale.Reproducibility is better than $6 NPA color unit.

Sediment is determined by filtration of the fuel to be tested through anasbestos mat in a Gooch crucible and reported as milligrams per liter.

212 F. STABILITY TEST in this test, 500 milliliters of the fuel to betested is placed in a beaker covered with a watch glass and the beakerkept for 24 hours at 212 R12 F. in a mechanically convccted oven. Coloris measured at the beginning, and color and sediment are measured at theend of the 24 hour period as described hereinbefore.

Briefly, the present method for stabilizing fuel oils with respect tocolor and/or sedimentation comprises contacting the unstable, i. e.,unstable with respect to color and/or sedimentation, fuel oil withactivated ion exchange materials. It is preferred to use such stronglybasic anionic exchange materials as Rohm and Haas XE- or IRA-400 or DowChemical Co. Dowex 1 or Dowex 2. Other ion exchange materials which canbe used are the more weakly basic anionic exchange material manufacturedby the Permutit Company and available as Permutit S, and by the Rohm andHaas Company and available as ill-45. Such treatment removes from theoil some or all of the constituents or precursors of constituents whichpromote instability with respect to color and/ or the formation ofsediment during storage.

The fuel oil after being contacted with the exchange material may bewater-washed. When only the catalytically cracked component is treatedit is then blended with the straight run component in such proportionsas determined by the exigencies of the situation. Fuel mixturescontaining 20 to percent of the catalytically cracked component areconventional. When the straight run component is sour it can either betreated in any suitable manner to convert the mercaptans andthinp'nenols to sulfides and blended with the treated catalyticallycracked component or the cracked and sour straight run components can beblended and the blend treated with ion exchange material. Such a blendis sweet and stabilized with respect to color and sedimentation. Whensweet straight run stock is to be blended with catalytically crackedstock the blend can be treated.

The fuel oil to be treated can be passed through one or more stationarybeds of activated ion exchange material, or co-current orcounter-current to a moving bed of activated ion exchange material orthe activated ion exchange material can be mixed with the fuel oil to betreated and the mixture agitated in a batch operation and the treatedoil separated from the exchange material.

Unactivated basic anion exchange materials are inoperative to producefuel oil stable to at least one of color and sediment. The basic anionexchange resin must be activated by contact with an aliphatic monohydricalcohol having 1 to 5 carbon atoms. Thus, fresh or regenerated anionexchange resin material in the :3 hydroxyl form is contacted in anysuitable manner with an aliphatic monohydric alcohol having 1 to carbonatoms. Thus, the resin can be immersed in the alcohol and then thealcohol drained oif or the alcohol can be allowed to percolate throughthe resin using about 5 volumes of alkanol per volume of resin asdescribed in co-pending application Serial No. 247,372, now U. S. PatentNo. 2,718,489, filed September 19, 1951, in the names of Harry L.Coonradt and Wilbur K. Leaman.

can be employed. In other words, the upper limit of the treatingtemperature range is limited by the decomposition point of the ionexchange material.

The data presented in Tables I. II and III were obtained by contactinganionic exchange resin, after activation by treatment with an alkanolhaving 1 to 5 carbon atoms, With either the sour straight run componentonly (Table I), the catalytically cracked component only (Table II) orboth the straight run and the catalytically cracked The ion exchangematerial can be regenerated by concomponents (Table III). Aftertreatment the straight tacting the exhausted ion exchange material withan run and catalytically cracked components were then alcohol solutionof caustic such as a 4 percent solution of blended in the ratio of 70volume percent catalytically sodium hydroxide or an aqueous solutioncontaining 2 cracked fuel oil to volume percent of straight run to 15percent alkali metal hydroxide. fuel oil.

Alternatively the anion exchange resin can be regen- I As indicated bythe data in Table 1, treatment of the erated in accordance with themethod described in costraight run component alone confers on the blenda pending application Serial No. 247,731, filed September limited degreeof stabilization with respect to sedimenta- 19, 1951, now Patent No.2,660,154, in the names of tion and there is no improvement in colorstability.

Table I 110 F. Test 212 F. Test Liquid Resin Fuel Oil Hourly Initial3Weoks BWeeks Example No. Used to Resin Space Color Ratio Velocity Bed,Sect, Total Color Mg./L. Color MgJL. Color Sod,

MgJL.

4.4 D114 4.4 D 1% 4.4 D 1% 4.4 D 13/ 4.4 D 1% 4.4 D 134 4.4 D 1% 4.4 D154 9 4.4 D 1% Control D 1, 4

D-dark; L-light.

Harry L. Coonradt and Wilbur K. Leaman. The method therein disclosedcomprises contacting exhausted anion exchange material with a solutionof alkali metal hydroxide Whilst passing free oxygen containing gasthrough said solution.

The fuel oil and ion exchange material during treatment are held at atemperature between about 60 F. to below the decomposition temperatureof the ion ex- The data presented in Table II were obtained when thecatalytically cracked component of the blend alone was treated. It willbe readily recognized that these blends of untreated sour straight runand treated catalytically cracked fuel oils are exceptionally stablewith regard to color and sedimentation. The blend comprised 70 volumepercent catalytically cracked fuel oil and 30 volume percent sourstraight run fuel oil.

50 mixture of resins. Based on each resin, not total volume. (NM-Sodiumform of resin.

change material. The temperature at which a substantial loss of ionexchange capacity occurs, the decomposition temperature, can bedetermined by keeping the resin at an elevated temperature for aprolonged period of time and then determining again the ion exchangecapacity of the resin. The lowest temperature at which a substantialloss of ion exchange capacity occurs is the decomposition temperature.The decomposition point of the aforementioned Rohm and Haas stronglybasic Amberlite resins is about 140 F. Of course, when the ion exchangematerial has a decomposition temperature The data presented in Table IIIwere obtained from runs in which both the catalytically cracked and thesour straight run fuel oils were treated. The resultant blend hadexcellent stability both with respect to color and sedimentation. Theuse of an anionic exchange material alone gives better results withrespect to color since the use of a cationic exchange material in thesodium cycle along with the anionic exchange material results in adarkening of the oil during treatment in the presence of the cationicexchange material. However, the stability with respect to both color andsedimentation higher than about F. higher treating temperatures 7 isgood.

Table III 110 1!. Test 212 1?. Test Fuel Liquid Example Component ResinUsed Oil to Hourly Initial 3 Weeks 6 Weeks No. Resin 8 see Color RatioVe ocity Oolor Bed. Color Bed., Oolor Sed., Mg L. gJL. Mg./L

4. 4 12 4. 4 13 4. 4 Sour Str. Run-- XE 75 4 4 14 Cat. Cracked 4. 4 SourStr. Run- 4.4 15 Cat. Cracked 4.4 Sour Sir. Run- X a 4.4 Oat.Oraekedunn.

Bour Str. Run

Oat. Oracked {Sweet Str. Run

1 Air-caustic sweetened straight run fuel oil. I LHSV based on eachresin rather than total volume.

color and/or stabilization are (1) a high degree of stabilization isobtained, (2) there is no significant loss of oil such as occurs intreatment with sulfuric acid and (3) there is no waste sludge disposalproblem as there is when the fuel oil is treated with sulfuric acid.

The strongly basic anion exchange resins which are preferred for thetreatment disclosed hereinbefore can be distinguished from the weaklybasic anion exchange resins. In general, the commercial ion exchangeresins vary considerably as to their basic strength and this isindicated by titration with hydrochloric acid. (Ion Exchange Resins,"

LHSV based on each resin.

Thus, it is apparent that the stability of a blend of catalyticallycracked and straight-run fuel oils can be stabilized with respect tocolor and sedimentation (1) by contacting the blend containingcatalytically cracked fuel oil and straight run fuel oil with activatedion exchange material, preferably with activated strongly basic anionicexchange material or (2) by contacting the catalytically crackedcomponent of the blend with activated ion exchange material, preferablywith activated strongly basic anionic exchange material and thenblending the treated catalytically cracked component with treatedstraight run fuel oil. It has been discovered that in the method of thepresent invention it is unnecessary to extractively sweeten, i. e.remove the mercaptans, but that it is suificient to convert themercaptans to sulfides or disulfides for example by contacting thestraight run component of the blend with aqueous alkali metal hydroxidesolution and gas containing free oxygen.

It is preferred to treat only the catalytically cracked component andthereafter blend the treated fuel oil with straight run fuel oil treatedby contact with air and aqueous alkali metal hydroxide solution.

The advantages of treatment of fuel oil as disclosed herein for thestabilization of fuel oils with respect to Kunin and Myers, Wiley andSons (1950), page 40.) For example, a representative weakly basic resinis neu tralized in the range of pH of about 7 to 2. The degree ofadsorption of a weak acid on a weakly basic ion exchange resin iscontrolled principally by the ionization constant of the acid. (IonExchange," F. C. Nachod, Academic Press, New York (1949), page 70) andcan be expressed quantitatively. In general, the weakly basic exchangeresins are not sufficiently basic to appreciably neutralize in aqueoussolutions such weak acids as silicic acid, carbonic acid, hydrocyauicacid, phenols and the like, whereas the strongly basic resins willneutralize such acids. (Ion Exchange, F. C. Nachod, page 66, and IonExchange Resins, Kunin and Myers, page 44.)

In general, a strongly basic ion exchange resin is one which ontitration with hydrochloric acid in electrolyte free water has a pHabove about 7.0 when the amount of hydrochloric acid added is one-halfof that required to reach the inflection or equivalence point. A weaklybasic ion exchange resin under the same conditions has a pH below about7.0 when one-half of the acid required to reach the equivalence pointhas been added.

Amberlite IRA-400 and Amberlite IRA-410 and XE-75, a more porous form ofIRA-400, are strongly basic anion exchange resins which, according tothe manufacturer, can be adequately described as styrene copolymerschloromethylated and aminated to quaternary ammonium hydroxidematerials. Dowex l and 2 are strongly basic anion exchange resins whichare quaternary amines having styrcnc-tlivinylbcnzene nuclei. PernitiiiiS is an anion exchange resin with a basicity intermediate the stronglybasic and the weakly basic anion exchange resins.

The present application is a continuation-in-part of copendingapplication for United States Letters Patent Serial No. 247,373, filedSeptember 19, 1951, and now abandoned, in the names of Harry L. Coonradtand Wilbur K. Leaman.

We claim:

1. A method for stabilizing heating oil with respect to at least one ofcolor and sedimentation which comprises contacting a heating oilcomprising at least 20 percent catalytically cracked heating oil with astrongly basic anion exchange resin which has previously been activatedby contact with an aliphatic monohydric alcohol having 1 to 5 carbonatoms, and separating contacted heating oil from said strongly basicanion exchange resin.

2. A method for stabilizing heating oil with respect to at least one ofcolor and sedimentation which comprises treating a straight run heatingoil to convert mercaptans into polysulfides in situ, contactingcatalytically cracked heating oil with activated strongly basic anionicexchange resin, said resin having becn previously activated by contactwith an aliphatic monohydric alcohol having 1 to 5 carbon atoms,separating treated catalytically cracked heating oil from said resin,and mixing said treated straight run heating oil with said treatedcatalytically cracked heating oil.

3. A method for stabilizing heating oil with respect to at least one ofcolor and sedimentation which comprises contacting a straight runheating oil with aqueous alkali metal hydroxide solution and air,separating the so-treated oil from said aqueous solution, water-washingsaid treated straight run heating oil, contacting catalytically crackedheating oil with strongly basic anionic exchange resin previouslyactivated by contact with an aliphatic monohydric alcohol having 1 to 5carbon atoms, separating treated catalytically cracked heating oil fromsaid resin, and mixing said treated straight run heating oil with saidtreated catalytically cracked heating oil.

References Cited in the file of this patent UNITED STATES PATENTS2,359,342 Winding Oct. 3, 1944 2,359,345 Winding Oct. 3, 1944 2,368,510Winding Jan. 30, 1945 2,718,489 Coonradt et al. Sept. 20, I955

1. A METHOD FOR STABILIZING HEATING OIL WITH RESPECT TO AT LEAST ONE OFCOLOR AND SEDIMENTATION WHICH COMPRISES CONTACTING A HEATING OILCOMPRISING AT LEAST 20 PERCENT CATALYTICALLY CRACKED HEATING WITH ASTRONGLY BASIC ANION EXCHANGE RESIN WHICH HAS PREVIOUSLY BEEN ACTIVATEDBY CONTACT WITH AN ALIPHATIC MONOHYDRIC ALCOHOL HAVING 1 TO 5 CARBONATOMS, AND SEPARATING CONTACTED HEATING OIL FROM SAID STRONGLY BASICANION EXCHANGE RESIN.